import javax.swing.JComponent;
import java.awt.Color;
import java.awt.Graphics;
import java.awt.Graphics2D;
import java.awt.geom.Ellipse2D;

public class TrafficLightComponent extends JComponent
{
   public void paintComponent(Graphics g)
   {
      Graphics2D g2 = (Graphics2D) g;
      // your work here
      g2.setColor(Color.red);
      g2.fillRoundRect(10,10,40,40,40,40);
      g2.setColor(Color.yellow);
      g2.fillRoundRect(10,60,40,40,40,40);
      g2.setColor(Color.green);
      g2.fillRoundRect(10,110,40,40,40,40);
      
   }
}